What's the difference between packages that start with @ and without?

Question

npm

Accidentally noticed when there were conflicts. 2 packages of slightly different versions were installed.
Prime

"@babel/core": "^7.8.3",
 "babel/core": "^7.8.3",

Everything seems to be the same, but in the case without @, the files are placed separately in node_modules, and everything with @babel will be in the babel folder.
It appears that some packages require babel/core while others require @babel/core. Because removing one of them breaks the assembly.